Upgrade or leave it alone

[raygan_gamer]

this is Windows XP Pro
ASUS A7N8X Deluxe ACPI BIOS Rev 1007, 10/8/2003
AMD Athlon XP 2400+ Thoroughbred
2GB Corsair XMS
Silvestone SST-ST60F (600watt)
CHENMING CMUI-601AEBL-W Blue (without side fan)


Used mainly for minor Photoshop, pic/movie storage, same old skool gaming (GhostRecon/RainbowSix/HL2) and hasn't received any love since building a second pc.

Just curious what upgrade could be further added or leave it as is.

I may build another PC (April 08---depends on tax return)...may try to learn watercooling (if anyone in Chicago is available to give hands-on tutorial)

Question:
Should I give this old workhorse a new heatsink fan or is case at least a prime candidate for future H20 cooling?

Advance thanks